Introduction: Easy Helmet Visor
Some bike helmets don't have an easy way to add a brim/visor. My wife found a ball cap with a plastic brim. Using a razor blade she excized it from the cap by cutting the stitches. Using the stitch holes make four equal slashes roughly matching the natural air vents in the helmet. Loosely connect and center the brim & wire ties on the helmet. Tighten slowly to contour the brim with thw helmet. You might want to use an odd number of holes if there is a center vent.
You will need a sacrificial baseball cap. Longish wire ties and a razor blade/sharp knife.